COMPARE RC, DIRECT AND TRANSFORMER COUPLING

Difference Between Three Common Couplings

sl.no.	Characteristics	RC Coupling	Transformer Coupling	Direct Coupling
1.	Size	Small	Large and Bulky	Very Small
2.	Cost	Small	Costlier	Very Small
3.	Frequency Response	Excellent in Audio Frequency	Poor	Best
4.	Impedence Matching	Not Good	Excellent	Good
5.	Application	Voltage Amplification	Power Amplification	Low Frequency Signal Amplification

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RC COUPLING

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Rc Coupling is the most Commonly used Coupling Between the two stages of a cascaded or multistage amplifier because it is cheaper in cost and Very compact circuit and provides excellent frequency response.

Eg:- Rc Coupled Amplifier


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IMPEDENCE COUPLING OR TRANSFORMER COUPLING

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Impedence Coupling results in more efficient amplification because no signal power is wasted in Inductor L.
Such Coupling has the drawback of being larger, Heavier and Costlier than the RC COUPLING. Impedence Coupling is rarely used beyond audio range.

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DIRECT COUPLING

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Direct coupling is essential for Very low frequency applications Such as photoelectric current.
It has got advantages of Simple and Very cheap circuit arrangement, outstanding ability to amplify low frequency signals.

The Drawbacks of Direct Coupling includes Poor Temperature stability and unsuitability for amplification of high frequency signals.

Direct coupled amplifiers are used When the load is Directly in series with the Output terminal of the active circuit element.

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